Cold starting aid system for an internal combustion engine and method of start-up sequencing for same

ABSTRACT

A cold starting system and power management software consisting of an air heater system, a fuel heater system, a controller with microprocessor and related software, a series of devices comprising of switches, indicators, solenoids and sensors, is used as an aid to assist start up of air cooled combustion engines in extreme temperature environments. Both the air and fuel heater systems include electrically powered heating elements. The power management software controls the sequential operation of individual system components.

[0001] (Divisional of US patent application Ser. No. 09/476,968, filedon Dec. 30, 1999, claiming priority from CA patent application2,293,134) This invention relates to a cold starting aid system forinternal combustion engines.

BACKGROUND OF THE INVENTION

[0002] Air-cooled internal combustion engines are employed in a varietyof applications in everyday life, from mopeds to family transport, largetrucks, and industrial power plants. Today's engines are designed tooperate reliably within a limited temperature range, typically between−20° C. to 40° C. When faced with extreme operating conditions, such aslow temperatures, consistent engine start up and operation cannot berelied upon without assistance.

[0003] In order to initiate the combustion of an air/fuel mixture in acombustion chamber of an engine, the internal energy of the mixture mustbe raised to a critical level. For gasoline engines, this is typicallyaccomplished through a compression of the air/fuel mixture and asubsequent ignition supplied by a spark plug. If the engine start up isnot achieved immediately, then power, supplied by a battery is used tocrank the engine over an extended period of time until the enginestarts. In extreme cold conditions, a block heater can sometimes berelied upon, to warm up the engine block and, thereby, raise theinternal energy of the fuel and air closest to the combustion chamber,in combination with the compression cycle and the ignition spark. Thedisadvantages of this start up aid is that it expends energy not usedduring start up, it requires time to warm up the engine block beforestarting can be tried, and an external energy source must be used topower the block heater. It is not uncommon for the battery to run out ofcharge at extreme cold temperatures before achieving start up.

[0004] In operation with diesel engines in extreme temperatureconditions, raising the internal energy of the air/fuel mixture isaccomplished by compression of the air/fuel mixture only, or bycompression and the use of an electric glow plug. These starting systemsare suitable only for smaller size engines with high compression ratioand high RPM (automobile diesel engines). Larger engines, like the onesof transport trucks, require different starting aids. Some are using thesame block heaters as for the gasoline engines. The block heaters arenot usually relied upon because of inaccessibility en-route (no externalpower source to connect the heater). Therefore, at low temperatures, itis not uncommon to leave the engine running rather than risk restart.Also, the use of a block heater is practical where the engine iswater-cooled, but in some applications air cooled engines are preferred.The start up of diesel engines can also experience other disadvantages,namely running down of the battery, extended start up times, andexcessive use of power resources.

[0005] One startup aid for diesel engines is to heat the intake air withfuel-fired (combusting) glow plugs. This starting aid is reliable onlyif the engine draws excess amounts of air through its intake manifold tosupply oxygen to both the fuel fired glow plugs and a fuel charge in thecombustion chamber. Otherwise, the fuel-fired glow plug can consume allthe oxygen in the air and “starve” the engine.

[0006] A particular problem arises where an internal combustion engineis used to drive stationery equipment, e.g. a generator or pump. Suchdevices are used intermittently and may remain idle or in storage forextended periods. The devices typically are transported to a remotelocation and the engine must be able to start quickly and reliablywithout significant preparation.

[0007] It is therefore an objective of the present invention to providea cold starting aid system and a starting method that will obviate ormitigate the above disadvantages.

SUMMARY OF THE INVENTION

[0008] In general terms, the present invention relates to a cold startsystem for internal combustion engines and its method of use. In oneaspect of the invention, there is provided a cold start system for anengine having at least one fuel injector and an air intake manifold tosupply fuel and air respectively, into a combustion chamber. The coldstart system includes at least one heating element to be disposed in theair intake manifold to heat a body of air and at least one heatingelement to be disposed around the fuel injector to heat the fuelcontained therein.

[0009] Preferably, a controller, including a series of switches, is usedto regulate a supply of power from a battery to the starter, and theplurality of heating elements. The controller is connected to amicroprocessor with associated power management software. The softwaredirects the controller by way of a feed back loop connected to anambient temperature sensor, to select an appropriate heating andcranking cycle. Additional sensors can be incorporated into thecontroller and include a RPM sensor which detects if the engine hasstarted, an oil pressure sensor which monitors the pressure of the oil,a water sensor which detects if there is water present in the fuel, anda range RPM sensor which detects if the speed of the engine is outsideof the normal operating range.

[0010] In a preferred embodiment, a fuel pre-heat system consists of aheater body mounted around the fuel injector. The body houses the fuelinjector and a thermally conductive gasket may be positioned between thebody and the fuel injector, to enhance heat transfer there between. Aplurality of heating elements are inserted into a series of holeslocated around an exterior of the body, which minimizes the distancebetween the fuel pre-heat system and the combustion chamber.

[0011] An air pre-heat system of a preferred embodiment includes aspacer located in the air intake manifold and a plurality of heatingelements. A series of ports are preferably located in a peripheral wallof the spacer, into which the heater elements are inserted. A thermalinsulator may be positioned between the spacer and the air intakemanifold. A plurality of insulating fasteners are used to mount thespacer to the air intake manifold and minimize heat transfer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features of the preferred embodiments of theinvention will become more apparent in the following detaileddescription in which reference is made to the appended drawings wherein:

[0013]FIG. 1 is a schematic representation of an internal combustionengine including a cold starting aid system.

[0014]FIG. 2 is a plan view of a fuel heater used in the system of FIG.1.

[0015]FIG. 3 is a section on the line A-A of FIG. 2.

[0016]FIG. 4 is a side view of an air heater.

[0017]FIG. 5 is a section on the line B-B of FIG. 4.

[0018]FIG. 6 shows details of start sequences.

[0019]FIG. 7 shows details of start sequences.

[0020]FIG. 8 shows details of start sequences.

[0021]FIG. 9 shows details of start sequences.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Referring to FIG. 1, a typical air-cooled internal combustionengine 10 includes a crank case 11, a crank shaft 12 connected to apiston 14 which is housed in a cylinder 16, and a to combustion chamber18 disposed between the piston 14 and cylinder 16. An air intakemanifold 24 and an exhaust manifold 26 are connected to the combustionchamber 18. A starter 22 is connected to the crankshaft 12. Anelectrical fuel pump 30 is connected by fuel lines 13 to a fuel injector28, which supplies the fuel 34 to the combustion chamber 18. The fuelpump 30 is controlled by a “Fuel ON” solenoid 31, and a “Fuel OFF”solenoid 32, to regulate the supply of electrical power from a battery56 to the pump 30. The voltage supplied to the system by the battery 56can be 12 volt DC or 24 volt DC. Incorporated in the engine 10 is a coldstarting aid system 8 consisting of a fuel heater 35 distributed aroundthe fuel injector 28 to heat the fuel 34, and an air heater 43positioned on the air intake manifold 24 to heat the air 33.

[0023] The fuel heater 35, shown in FIGS. 2 and 3, includes a heaterbody 38, which is mounted onto the cylinder 16 of FIG. 1, and a recess42 in the body 38 to encompass the body of the fuel injector 28. Athermally conductive gasket 40 is positioned between the heater body 38and the injector 28 to enhance the transference of heat therebetween. Aplurality of heating elements 37, which in the preferred embodiment areelectric Firerod cartridges, are inserted into a plurality ofcorresponding holes 41 located around an exterior of the heater body 38.These heating elements 37 are powered by the battery 56 of FIG. 1.

[0024] The air heater 43 of the preferred embodiment, shown in FIGS. 4and 5, includes a spacer 48 and a plurality of heating elements 36. Aseries of ports 44 are located in a peripheral wall 46 of the spacer 48in a staggered orientation, into which the heater elements 36 areinserted. In the preferred embodiment, the air heating elements areelectric Glow plugs that are powered by a 12 volt DC battery 56. Forsystems that use 24 volt DC power, the spacer 48 is divided into a firstportion 47 and a second portion 49. An electrical insulator 51 issandwiched between the portions 47, 49, of the spacer 48, in order toseparate the electrical grounds of the two portions 47, 49. A thermalinsulator 50 is positioned between the spacer 48 and the air intakemanifold 24, to help inhibit thermal transfer to the rest of the engine10, which may act as a thermal heat sink. The same thermal insulator 50acts as an electrical insulator, which electrically isolates the spacerfrom the air manifold 24. A wraparound housing 80, made of a thermallyconductive material, such as aluminum, is installed on both sides of thespacer 48 in order to protect the heating elements 36 from the inclusionof foreign matter. A plurality of insulating fasteners 45 are used tomount the spacer 48, thermal insulator 50, and wraparound housing 80 tothe air manifold 24.

[0025] A controller 52, including a series of switches 54, is used toregulate the supply of power from the battery 56 to the starter 22, the“Fuel ON” solenoid 31, the “Fuel OFF” solenoid 32, and the heatingelements 36. The controller 52 is connected to a microprocessor withreal time clock 62 and is controlled by the associated power managementsoftware 60. The software 60 directs the controller 52 by way of afeedback loop 57 connected to a temperature sensor 58 to select anappropriate heating and cranking cycle. The heating/cranking cycledepends of the ambient temperature read by the temperature sensor 58. Inthe preferred embodiment, the temperature of the oil 9 in the crankcase11 is monitored for an indication of ambient temperature. Additionalsensors can be included to feed various signals into the controller, inorder to monitor the engine operation. Examples of additional sensorsinclude a proximity sensor 64 which detects if the engine 10 hasstarted, an oil pressure sensor 66 which monitors the pressure of theoil 9, a water in fuel sensor 68 which detects if there is water presentin the fuel 34, and a range RPM sensor 70 which detects if the speed ofthe engine 10 is outside of the normal operating range. All the run orfault states monitored by the various sensors are indicated on thecontroller 54 by a series of indicators 69.

[0026] The operation of the cold starting aid system 8 in connectionwith the internal combustion engine 10 is directed by a series ofdifferent start up sequences 71, 72, 73, 74, 75, 76, 77 and 78, given inFIGS. 6 through 9. Each of the start up sequences 71-78 provides adifferent sequence of the operation of the starter 22, fuel pump 30,solenoids 31, 32, and heating elements 36, 37. The sequencing logic ofthe power management software 60 directs the order in which thecomponents 22, 31, 32, 36, 37 are enabled or disabled, in order tominimize the amount of power required for start up of the engine 10. Incertain instances the air 33 and the fuel 34, either simultaneously orseparately, are heated for a certain delta time unit before beingdelivered into the combustion chamber 18. In other instances, the air 33and fuel 34 are delivered into the combustion chamber 18 without theapplication of heat.

[0027] The power management software 60 selects which of the particularstartup sequences 71-78 is followed, preferably based on the ambienttemperature measured by the temperature sensor 58 in the oil 9. By wayof example only, an outline of the start up sequence 77 for thetemperature range −32° C. to −41° C. shown in FIG. 9 is now described.

[0028] For the first six seconds the starter 22 is de-energized and thefuel pump 30 and the air and fuel heaters 35, 43 are energized, therebyheating the air 33 situated near the spacer 48 and heating the fuel 34deposited into the fuel injector 28 by the pump 30, before thecrankshaft 12 is rotated. After the sixth second until the end of thefifteenth second the fuel pump 30 is de-energized, the starter 22remains de-energized, and the fuel and air heating systems 35, 43 remainenergized, thereby further heating of the air 33 near the spacer 48 andheating of the fuel 34 retained in the injector 28. After the fifteenthsecond until the end of the eighteenth second the fuel pump 30 isenergized, the fuel and air heating systems 35, 43 are de-energized, andthe starter 22 is energized, thereby allowing the pre-heated air 33 andthe pre-heated fuel 34 to be drawn into the combustion chamber 18 as thecrankshaft 12 is rotated. Further amounts of fuel 34 and air 33 suppliedto the combustion chamber IS are not pre-heated. After the eighteenthsecond until the end of the thirtieth second all the components 30, 35,43 and 22 are energized, whereby the fuel 34 and the air 33 are heatedas they flow into the combustion chamber 18, during rotation of thecrankshaft 12. If the engine 10 starts, the proximity sensor 64 detectsthe increase in speed and directs the controller 52 to stop the heatingand cranking cycle.

[0029] If after the thirtieth second the engine 10 has not started, thefuel pump 30 and the starter 22 are de-energized while the fuel and airheating systems 35, 43 remain energized until the thirty ninth second.These systems 35, 43 continue to pre-heat the air 33 situated in thevicinity of the spacer 48 and the fuel 34 retained in the injector 28,before the crankshaft 12 is further rotated. After the end of the thirtyninth second until the end of the forty fifth second the fuel pump 30and starter 22 are energized and the fuel and air heating systems 35, 43are de-energized, thereby supplying the pre-heated air 33 and thepre-heated fuel 34 to the combustion chamber 18, during crankshaft 12rotation. Further amounts of fuel 34 and air 33 supplied to thecombustion chamber 18 are not pre-heated. After the forty fifth seconduntil the end of the sixtieth second all the components 30, 35, 43, and22 are energized, whereby the air 33 and fuel 34 supplied to thecombustion chamber 18 are pre-heated as the crankshaft 12 is rotated.

[0030] The start-up sequence 77 is completed after the end of thesixtieth second, where by this point if the engine 10 has not startedthe sequence 77 can be repeated up to four times. The proximity sensor64 will interrupt the start up sequence 77, once the engine 10 hasstarted, at any time during the ignition process. The other sensors 66,68, and 70 can also interrupt the ignition process.

[0031] Different ambient temperatures will initiate different sequencesas indicated by the sequences 71-76 and 78 where a “1” indicates anenergized state and “0” indicates a de-energized state. It should benoted that sequence repetition and interruption is experienced by theother startup sequences 71-76 and 78 as well.

[0032] The cold starting aid system 8 can be used with 12 volt DC and 24volt DC batteries 56. The fuel heating elements 37 in the preferredembodiment are electric Firerod cartridge plugs and are preferablypressed into the holes 41 of the heater body 38. The heater body 38 ismade of a conductive material, such as aluminum. The casket 40 betweenthe body 38 and injector 28 is made of a silicone based compoundcontaining zinc oxide, such as Wakefield Engineering Thermal JointCompound, which is typically malleable in order to fill in the spacebetween the body 38 and injector 28. Placement of the fuel heater 35around the fuel injector 28 minimizes the distance between the heater 35and the combustion chamber 18, shown in FIG. 1. This results in heatingof the fuel 34 closest to the combustion chamber 18 which inhibits thepotential risk of vaporizing the fuel 34 in the fuel lines 13, wherebyvapor lock can occur. The air heating elements 36 in the preferredembodiment, are electric Glow plugs and are preferably threaded into theports 44 of the spacer 48. The use of non-combusting heaters 36 in theair intake 24 ensures that the air 33 is heated without depleting theoxygen in the air 33 inside the intake manifold 24. The thermalinsulator 50, the electrical insulator 51, and the fastener 45 are madeof an insulating material such as Teflon.

[0033] During testing, the heat output of the four Fireroad cartridgesused as fuel heating elements 37 to heat the fuel 34 in the vicinity ofthe fuel injector 28, reached a maximum of 200 watts in less than 4seconds. The four Glow plugs used as air heating elements 36, for theair heater 43, obtained a maximum heat output of 480 watts in less than4 seconds. The amount of heat generated to heat the fuel 34 and air wasadequate and enough to produce a reliable engine start in less than oneminute, and a sustained operation for all ambient temperature rangesinvestigated.

[0034] All of the start up sequences 71-78 are typically of one minutein duration. These ignition processes can be repeated up to four timesand are interruptible if the proximity sensor 64 detects that the engine10 has started. The oil temperature ranges tested were 140° C. to 4° C.for sequence 71, 4° C. to 4° C. for sequence 72, −4° C. to −12° C. forsequence 73, −12° C. to −18° C. for sequence 74, −18° C. to −25° C. forsequence 75, −25° C. to −32° C. for sequence 76, −32° C. to 41° C. forsequence 77, and −41° C. to −55° C. for sequence 78. The temperature ofother mediums, such as the ambient air, can also be used as input to thepower management software 60.

[0035] Although the invention has been described with reference tocertain specific embodiments, various modifications thereof will beapparent to those skilled in the art without departing from the spiritand scope of the invention as outlined in the claims appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A cold start system foran engine having at least one fuel injector for supplying fuel to acombustion chamber and an air intake manifold for supplying air to acombustion chamber, said cold start system including at least oneheating element to be disposed in said manifold for heating a body ofair therein and a heater to be disposed on said injector for heating thefuel contained therein.
 2. A cold start system according to claim 1,wherein said heater is adapted to encompass a body of said injector. 3.A cold start system according to claim 2, wherein said heater includes abody and at least one electrical heating element disposed in said body.4. A cold start system according to claim 3, wherein said heaterincludes a heat conductive gasket to be interposed between said body andsaid injector.
 5. A cold start system according to claim 4, wherein saidbody includes a recess for receiving said injector and a plurality ofelectrical heating elements are located in said body adjacent to saidrecess for transferring heat to said injector.
 6. A cold start systemaccording to claim 1, wherein said heating element disposed iselectrically activated.
 7. A cold start system according to claim 6,further comprising a controller for monitoring the operation of saidsystem.
 8. A cold start system according to claim 7, wherein saidcontroller manages a plurality of switches for monitoring the cyclicoperation of said heating elements and said heater.
 9. A cold startsystem according to claim 6 including a spacer for mounting in saidmanifold, said spacer having a peripheral wall and said heating elementbeing located on said peripheral wall.
 10. A cold start system accordingto claim 9, wherein said heating elements are distributed on saidperipheral wall and project inwardly therefrom for providing uniformheating of air within said manifold.
 11. A cold start system accordingto claim 9, wherein said spacer is divided into first and secondportions and an insulator is interposed between said portions forinhibiting electrical transfer therebetween.
 12. A cold start systemaccording to claim 9 including thermally insulating gaskets on oppositesides of said spacer, whereby said spacer is thermally isolated fromsaid manifold.
 13. A cold start system according to claim 9 furthercomprising a housing adjacent to said spacer for inhibiting contact offoreign matter with said heating elements.
 14. A cold start systemaccording to claim 9 including a plurality of insulating fasteners tocouple said spacer to said manifold.
 15. A cold start system accordingto claim 7, wherein said controller varies operation of said heatingelements and said heater in response to variations in ambienttemperature.
 16. A cold start system according to claim 7, wherein saidcontroller comprises a microprocessor with a real time clock andassociated software for managing an appropriate start up cycle.
 17. Acold start system according to claim 7, wherein said controller monitorspredetermined operating parameters and is operable to inhibit operationof the engine in the event that a sensed parameter is outside of apredetermined operating range.
 18. A cold start system according toclaim 17, wherein said sensed parameter is selected from a groupcomprising information from a proximity sensor, oil temperature, oilpressure, engine rpm, and the presence of water in the fuel.
 19. A coldstart system according to claim 18 further including an indicator toshow said sensed parameter outside of said predetermined operatingrange.
 20. A cold start system according to claim 19, wherein saidindicator is a light.
 21. A cold start system according to claim 7,wherein a controller initiates the operation of said heating elementsand said heater and terminates said operation after a predeterminedinterval.
 22. A cold start system according to claim 7, wherein saidcontroller monitors an operation of said fuel pump and a supply of fuelto said injector during operation of said heating element and saidheater.
 23. A cold start system according to claim 7, wherein saidcontroller monitors an operation of said fuel pump and a supply of fuelto said injector during operation of said heating element and saidheater.
 24. An air cooled internal combustion engine comprising acrankshaft; a piston operably associated with said crankshaft andreciprocal within a cylinder; a combustion chamber formed between saidpiston and cylinder; an air intake system for supplying combustion airto said combustion chamber including a manifold and at least one heatingelement disposed in said manifold; a fuel injection system for supplyingfuel to said combustion chamber and including a fuel injector, a fuelpump for delivering fuel to said injector and a heater disposed on saidinjector for heating the fuel contained therein; a starter for rotatingsaid crankshaft; and a controller for monitoring operation of saidheating element, said heater and said starter; whereby the starting ofsaid engine is facilitated.
 25. An engine according to claim 24 whereinsaid controller inhibits operation of said starter during operation ofsaid heating element and said heater.
 26. An engine according to claim24 wherein said controller inhibits operation of said fuel pump duringoperation of said heating element and said heater.
 27. An engineaccording to claim 24 wherein said heating element is an electricallyoperated element disposed in said manifold.
 28. An engine according toclaim 24 wherein said heater is an electrically operated element coupledto said injector.
 29. A method of starting an internal combustion enginehaving an intake manifold for supplying air to a combustion chamber anda fuel injector for supplying fuel to said combustion chamber, saidmethod comprising the steps of; heating of air in said manifold for apredetermined time period; heating of fuel in said injector for apredetermined time period; and operating a starter for delivering saidair and said fuel into said combustion chamber for initiatingcombustion.
 30. A method according to claim 29 further including thestep of sensing an ambient temperature and selecting one of a pluralityof said predetermined time periods.
 31. A method according to claim 29further including the step of inhibiting operation of said starterduring said heating.
 32. A method according to claim 29 furtherincluding the step of inhibiting said heating of said fuel duringoperation of said starter.
 33. A method according to claim 29 furtherincluding the step of inhibiting said heating of said air duringoperation of said starter.
 34. A method according to claim 29 furtherincluding the step of indicating to a user a plurality of operationalstates of said engine.